Overpopulation is not the cause of global warming. Most carbon is produced through the endless consumption of the economies of Europe and the US. It is not from places with high populations.
These talking points must be fought whenever and wherever they arise.
I’ve tried bringing up ‘per capita’ consumption rates of the first world and specifically the US to these people and suddenly all their ‘reasonable debatelord’ energy goes right out the window and ‘that’ll never happen so why discuss it’ (because it involves them making a personal sacrifice)